Fig. 3. Electromotor responses to changes in contrast of the electrosensory image of a cylindrical object. (A,B) Mean ± S.D. of the normalized intervals (1-I/I₀) plotted as a function of the interval order (N=10 trials). (A) The increase of electric image contrast elicits a typical novelty response characterized by a shortening of the first two intervals after the change in image contrast followed by a slow relaxation curve. Note the significant increase in the S.D. (ANOVA, P<0.01). (B) The same change in contrast but in opposite direction does not elicit a novelty response although there is a significant increase of variability (ANOVA, P<0.01). (C) Single trial recordings of the local electric organ discharge (LEOD) illustrating the experimental paradigm.